HAVANA, Aug 6 (Reuters) - Cuba's hopes for energy
independence suffered another blow on Monday when its state oil
company said the island's latest offshore oil well was not
successful.

Cubapetroleo said the well drilled by Malaysia's state-owned
Petronas in partnership with Russia's Gazprom Neft found oil but
in a geological formation so tightly compacted that oil and gas
could not flow through it in "significant quantities."

"It cannot be qualified as a commercial discovery," the
company said in an announcement in the Communist Party newspaper
Granma.

It was the third failed well in three attempts in Cuba's
part of the Gulf of Mexico, where the communist country has said
it may have 20 billion barrels of oil.

The government led by President Raul Castro needs the oil to
free it from dependence on socialist ally Venezuela, which under
an oil-for-services deal sends Cuba about 115,000 barrels of oil
daily.

With Venezuelan President Hugo Chavez battling cancer and
facing re-election in October, the future of his oil largess for
Cuba is uncertain.

Cuba produces about 50,000 barrels a day from onshore wells,
but it consumes an estimated 147,000 barrels daily and refines
most of the rest for sale to other Caribbean countries.

Spanish oil company Repsol hit a dry hole in Cuban
waters in May and said it would likely pull out of the country
after 12 years of operations, two unsuccessful wells and
expenditures of $125 million.

Its first well, drilled in 2004, found oil but, like the
Petronas well, was deemed not commercially viable.

Repsol's recent well, drilled north of Havana in partnership
with Norway's Statoil and ONGC Videsh, a unit of
India's ONGC, found no hydrocarbons at all.

Cubapetroleo said the Petronas well, completed on July 31,
was drilled west of the Cuban capital in 7,408 feet (2,258
meters) of water, much deeper than Cuban and Petronas officials
previously had suggested.

EXTENDED OIL ZONE

It said the oil that was found "could extend to other zones"
in the four offshore blocks leased by the two companies and
perhaps beyond.

Petronas and Gazprom would continue to study data
collected during the drilling and conduct more seismic studies,
Cubapetroleo said.

Despite the three failed wells, Cuba oil expert Jorge Pinon
at the University of Texas in Austin said it is likely Cuba does
have offshore oil, but that finding and producing it will take
years.

"The bottom line is that Cuba is not going to get any
economic benefit from an oil find any time soon. This is a
long-term exercise - it's going to take a long time to get
results," he said.

One problem facing Cuba is that its potential fields are
mostly in what the oil industry calls "ultra-deep water," which
requires specialized drilling rigs not readily available to the
island because of technology limitations imposed by the
longstanding U.S. trade embargo.

Repsol spent years finding and waiting for the newly-built
Scarabeo 9 rig as it was constructed in China. It is owned by
Italian oil service company Saipem.

The rig will now go to Venezuela's PDVSA to drill a well at
Cuba's western tip, Cubapetroleo said, but after that its future
is not clear.

The Scarabeo 9 is contracted to stay in Cuba only until July
2013 and could leave earlier if no other company wants it.

Once it is gone, it will take a while to find another
deepwater rig to continue the exploration of Cuban fields.

"Whatever the scenario on this (Petronas) well and PDVSA's
is totally irrelevant in the short-term since the Scarabeo 9
will be gone," Pinon said.

Several other companies hold exploration blocks in Cuban
waters, but none are known to have firm drilling plans.
Petrovietnam has said it would wait to see the results of these
first wells before deciding what to do in its three exploration
blocks.

ONGC Videsh has said it is seeking partners to share the
high cost of drilling its two blocks.

Cuba's offshore drilling has stirred environmental concerns
in Florida, where fears that a repeat of the 2010 BP blowout in
the U.S. Gulf of Mexico could damage the state's beaches and
coral reefs.

The BP well spewed nearly 5 million barrels of oil into the
gulf and onto hundreds of miles of beaches in Florida and other
states. Cuban officials say they have taken all precautions to
guard against a similar accident.
(Editing by Kevin Gray and Carol Bishopric)